Just my take but regarding the missing fences and ballast colours, at face value it seems like a minor and insignificant issue, but you’ve got to factor in what these fences and ballast means and what they are used for. I will explain below; Here, we can see the TSW version and in real life version of the route. Both screenshots are in the same location. Almost immediately you notice the missing fences. But why is that so important? Firstly, it separates the High Speed 1 lines from the conventional National Rail C2C and freight lines, as seen to the left and right of HS1. This is very obvious in the real life picture, however in the TSW picture, it doesn’t feel like you’re driving on HS1, because there’s no separation of the lines. You could almost ask yourself which line is supposed to be the High Speed one, as they all look the same. Secondly, the ballast colour is exactly the same as what you’d expect to find on a conventional National Rail line, not a High Speed line. The lighter looking ballast isn’t limited to HS1, as a lot of High Speed lines use the lighter looking ballast variant. Next of all, the elevation of HS1 is slightly higher than of the adjacent lines. However TSW does not represent this. Finally, I did not see any sound barriers. This is, as you guessed, used for reducing sound pollution as trains speed past.